Beginning of oral medication approach to treating disc degeneration....
Diffusion of Human Lumbar Intravertebral Discs can be Enhanced Pharmacologically
With Oral Nimodipine
S. Rajasekaran, Ph.D., J. Naresh Babu, MS K.S. Murugan, MD Ajoy Prasad Shetty, MS
Introduction: Histological studies have documented that Calcium channel antagonist
Nimodipine increases vascularity of end plates in rats. However, there is no corresponding data
for humans and whether endplate hypervascularity leads to increase in diffusion. This prospective
study in human volunteers reports for the first time in literature an increase in diffusion following
Nimodipine by serial post contrast MRI study.
Methods: Forty lumbar end plates of four young healthy male volunteers formed the study
material. The pre-drug diffusion levels were studied by pre and post contrast MRI (0.3 mmol/kg
of gadodiamide) at 10 minutes, two, four, six, 12 and 24 hours. After a gadodiamide wash out
period of 10 days, a plain MR examination was performed to ensure return of signal intensity
values to the base line. Oral Nimodipine was administered (30 mgs QID) for five days following
which diffusion studies were performed by a similar MRI sequence. Enhancement was calculated
at different regions of interest (ROI) - vertebral body- VB; subchondral region-SCB; Endplate
Zone-EPZ and at superior and inferior peripheral nucleus pulposus-PNP and central nucleus
pulposus-CNP, using appropriate cursors by a blinded investigator. Paired sample t-test and area
under curve (AUC) measurements were performed to compare the pre and post-drug signal
intensities.
Results: Nimodipine was found to increase the signal intensity for all ROI significantly pre and
post contrast at all time intervals (p>0.01). The maximum difference in enhancement was at 10
minutes at VB; two hours for SB and EPZ; four hours for PNP and 12 hours for CNP. There was
also a significant increase for AUC at all ROI pre and post nimodipine showing that nimodipine
increases diffusion(p>0.01).
Conclusion: This is the first study to document an increase in diffusion of human lumbar discs
by oral nimodipine and poses interesting possibility of pharmacological enhancement of lumbar
disc diffusion.
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